Brandt, 1835 Aspidochirotida
Grube, 1840 Dendrochirotida
Grube, 1840 Elasipodida
Théel, 1882 Molpadida
Haeckel, 1896

Thelenota ananas, a giant sea cucumber from the Indo-Pacific

Sea cucumbers are echinoderms from the class Holothuroidea. They are marine animals with a leathery skin and an elongated body containing a single, branched gonad. Sea cucumbers are found on the sea floor worldwide. The number of holothurian (/ˌhɒləˈθjʊəriən, ˌhoʊ-, -ˈθʊər-/[2][3]) species worldwide is about 1,717[4] with the greatest number being in the Asia Pacific region.[5] Many of these are gathered for human consumption and some species are cultivated in aquaculture systems. The harvested product is variously referred to as trepang, bêche-de-mer or balate. Sea cucumbers serve a useful role in the marine ecosystem as they help recycle nutrients, breaking down detritus and other organic matter after which bacteria can continue the degradation process.[5] Like all echinoderms, sea cucumbers have an endoskeleton just below the skin, calcified structures that are usually reduced to isolated microscopic ossicles (or sclerietes) joined by connective tissue. In some species these can sometimes be enlarged to flattened plates, forming an armour. In pelagic species such as Pelagothuria natatrix (Order Elasipodida, family Pelagothuriidae), the skeleton is absent and there is no calcareous ring.[6] The sea cucumbers are named after their resemblance to the fruit of the cucumber plant.


1 Overview 2 Anatomy

2.1 Body plan 2.2 Digestive system 2.3 Nervous system 2.4 Respiratory system 2.5 Circulatory systems 2.6 Locomotive organs 2.7 Endoskeleton

3 Life history and behaviour

3.1 Habitat 3.2 Locomotion 3.3 Diet 3.4 Communication and sociability 3.5 Reproduction 3.6 Development 3.7 Symbiosis
and commensalism 3.8 Predators and defensive systems 3.9 Estivation

4 Phylogeny and classification 5 Holothurians as food and medicine 6 Commercial harvest

6.1 Black market

7 Aquaculture 8 In art and literature 9 See also 10 Notes 11 Citations


Sea cucumber : a -Tentacles, b - Cloaca, c - Ambulacral feet on the ventral side, d -Papillae on the back.

Most sea cucumbers, as their name suggests, have a soft and cylindrical body, more or less lengthened, rounded off and occasionally fat in the extremities, and generally without solid appendages. Their shape ranges from almost spherical for "sea apples" (genus Pseudocolochirus) to serpent-like for Apodida
or the classic sausage-shape, while others resemble caterpillars. "The mouth is surrounded by tentacles, which can be pulled back inside the animal."[7] Holothurians measure generally between 10 and 30 centimeters long, with extremes of some millimeters for Rhabdomolgus ruber and up to more than 3 meters for Synapta maculata. The largest American species, Holothuria
floridana, which abounds just below low-water mark on the Florida
reefs, has a volume of well over 500 cubic centimeters (31 cu in),[8] and 25–30 cm (10–12 in) long. Most possess five rows of tube feet (called "podia"), but Apodida
lacks these and moves by crawling; the podia can be of smooth aspect or provided with fleshy appendages (like Thelenota ananas). The podia on the dorsal surface generally have no locomotive role, and are transformed into papillae. At one of the extremities opens a rounded mouth, generally surrounded with a crown of tentacles which can be very complex in some species (they are in fact modified podia); the anus is postero-dorsal. Holothurians do not look like other echinoderms at first glance, because of their tubular body, without visible skeleton nor hard appendixes. Furthermore, the fivefold symmetry, classical for echinoderms, although preserved structurally, is doubled here by a bilateral symmetry which makes them look like chordates. However, a central symmetry is still visible in some species through five 'radii', which extend from the mouth to the anus (just like for sea urchins), on which the tube feet are attached. There is thus no "oral" or "aboral" face as for sea stars and other echinoderms, but the animal stands on one of its sides, and this face is called trivium (with three rows of tube feet), while the dorsal face is named bivium. A remarkable feature of these animals is the "catch" collagen that forms their body wall.[Notes 1] This can be loosened and tightened at will, and if the animal wants to squeeze through a small gap, it can essentially liquefy its body and pour into the space. To keep itself safe in these crevices and cracks, the sea cucumber will hook up all its collagen fibers to make its body firm again.[9] The most common way to separate the subclasses is by looking at their oral tentacles. Order Apodida
have a slender and elongate body lacking tube feet, with up to 25 simple or pinnate oral tentacles. Aspidochirotida
are the most common sea cucumbers encountered, with a strong body and 10–30 leaf like or shield like oral tentacles. Dendrochirotida
are filter-feeders, with plump bodies and 8–30 branched oral tentacles (which can be extremely long and complex).

Details of the mouth with its tentacles.

Synaptula lamperti
Synaptula lamperti
lives on sponges (here in Indonesia).

Synapta maculata, the longest known sea cucumber (Apodida).

The king sea cucumber (Thelenota anax, Stichopodidae
family) is one of the heaviest known holothurians.

Chiridota heheva, abyssal species.

Cucumaria miniata, a filter-feeding sea cucumber.

("sea apple").


Isostichopus badionotus

Thelenota rubralineata


Bohadschia argus

Anatomy[edit] Sea cucumbers are typically 10 to 30 cm (3.9 to 11.8 in) in length, although the smallest known species are just 3 mm (0.12 in) long, and the largest can reach 3 meters (9.8 ft). The body ranges from almost spherical to worm-like, and lacks the arms found in many other echinoderms, such as starfish. The anterior end of the animal, containing the mouth, corresponds to the oral pole of other echinoderms (which, in most cases, is the underside), while the posterior end, containing the anus, corresponds to the aboral pole. Thus, compared with other echinoderms, sea cucumbers can be said to be lying on their side.[10]

Conspicuous Sea Cucumber, Coconut Island, Hawaii

Body plan[edit] The body of a holothurian is roughly cylindrical. It is radially symmetrical along its longitudinal axis, and has weak bilateral symmetry transversely with a dorsal and a ventral surface. As in other Echinozoans, there are five ambulacra separated by five ambulacral grooves, the interambulacra. The ambulacral grooves bear four rows of tube feet but these are diminished in size or absent in some holothurians, especially on the dorsal surface. The two dorsal ambulacra make up the bivium while the three ventral ones are known as the trivium.[11] At the anterior end, the mouth is surrounded by a ring of tentacles which are usually retractable into the mouth. These are modified tube feet and may be simple, branched or arborescent. They are known as the introvert and posterior to them there is an internal ring of large calcareous ossicles. Attached to this are five bands of muscle running internally longitudinally along the ambulacra. There are also circular muscles, contraction of which cause the animal to elongate and the introvert to extend. Anterior to the ossicles lie further muscles, contraction of which cause the introvert to retract.[11] The body wall consists of an epidermis and a dermis and contains smaller calcareous ossicles, the types of which are characteristics which help to identify different species. Inside the body wall is the coelom which is divided by three longitudinal mesenteries which surround and support the internal organs.[11] Digestive system[edit]

A sea cucumber atop gravel, feeding

A pharynx lies behind the mouth and is surrounded by a ring of ten calcareous plates. In most sea cucumbers, this is the only substantial part of the skeleton, and it forms the point of attachment for muscles that can retract the tentacles into the body for safety as for the main muscles of the body wall. Many species possess an oesophagus and stomach, but in some the pharynx opens directly into the intestine. The intestine is typically long and coiled, and loops through the body three times before terminating in a cloacal chamber, or directly as the anus.[10] Nervous system[edit] Sea cucumbers have no true brain. A ring of neural tissue surrounds the oral cavity, and sends nerves to the tentacles and the pharynx.The animal is, however, quite capable of functioning and moving about if the nerve ring is surgically removed, demonstrating that it does not have a central role in nervous coordination. In addition, five major nerves run from the nerve ring down the length of the body beneath each of the ambulacral areas.[10] Most sea cucumbers have no distinct sensory organs, although there are various nerve endings scattered through the skin, giving the animal a sense of touch and a sensitivity to the presence of light. There are, however, a few exceptions: members of the Apodida
order are known to possess statocysts, while some species possess small eye-spots near the bases of their tentacles.[10] Respiratory system[edit] Sea cucumbers extract oxygen from water in a pair of "respiratory trees" that branch in the cloaca just inside the anus, so that they "breathe" by drawing water in through the anus and then expelling it.[12][13] The trees consist of a series of narrow tubules branching from a common duct, and lie on either side of the digestive tract. Gas exchange occurs across the thin walls of the tubules, to and from the fluid of the main body cavity. Together with the intestine, the respiratory trees also act as excretory organs, with nitrogenous waste diffusing across the tubule walls in the form of ammonia and phagocytic coelomocytes depositing particulate waste.[10] Circulatory systems[edit] Like all echinoderms, sea cucumbers possess both a water vascular system that provides hydraulic pressure to the tentacles and tube feet, allowing them to move, and a haemal system. The latter is more complex than that in other echinoderms, and consists of well-developed vessels as well as open sinuses.[10] A central haemal ring surrounds the pharynx next to the ring canal of the water vascular system, and sends off additional vessels along the radial canals beneath the ambulacral areas. In the larger species, additional vessels run above and below the intestine and are connected by over a hundred small muscular ampullae, acting as miniature hearts to pump blood around the haemal system. Additional vessels surround the respiratory trees, although they contact them only indirectly, via the coelomic fluid.[10] Indeed, the blood itself is essentially identical with the coelomic fluid that bathes the organs directly, and also fills the water vascular system. Phagocytic coelomocytes, somewhat similar in function to the white blood cells of vertebrates, are formed within the haemal vessels, and travel throughout the body cavity as well as both circulatory systems. An additional form of coelomocyte, not found in other echinoderms, has a flattened discoid shape, and contains hemoglobin. As a result, in many (though not all) species, both the blood and the coelomic fluid are red in colour.[10]

Pearsonothuria graeffei
Pearsonothuria graeffei
showing its three row of podia on its trivium

Sea cucumber
Sea cucumber
ossicles (here "wheels" and "anchors")

has been reported in high concentrations in holothurian blood,[14] however researchers have been unable to reproduce these results.[15] Locomotive organs[edit] Like all echinoderms, sea cucumbers possess pentaradial symmetry. However, because of their posture, they have secondarily evolved a degree of bilateral symmetry. For example, because one side of the body is typically pressed against the substratum, and the other is not, there is usually some difference between the two surfaces (except for Apodida). Like sea urchins, most sea cucumbers have five strip-like ambulacral areas running along the length of the body from the mouth to the anus. The three on the lower surface have numerous tube feet, often with suckers, that allow the animal to crawl along; they are called trivium. The two on the upper surface have under-developed or vestigial tube feet, and some species lack tube feet altogether; this face is called bivium.[10] In some species, the ambulacral areas can no longer be distinguished, with tube feet spread over a much wider area of the body. Those of the order Apodida
have no tube feet or ambulacral areas at all, and burrow through sediment with muscular contractions of their body similar to that of worms, however five radial lines are generally still obvious along their body.[10] Even in those sea cucumbers that lack regular tube feet, those that are immediately around the mouth are always present. These are highly modified into retractile tentacles, much larger than the locomotive tube feet. Depending on the species, sea cucumbers have between ten and thirty such tentacles and these can have a wide variety of shapes depending on the diet of the animal and other conditions.[10] Many sea cucumbers have papillae, conical fleshy projections of the body wall with sensory tube feet at their apices.[16] These can even evolve into long antennae-like structures, especially on the abyssal genus Scotoplanes. Endoskeleton[edit] Echinoderms typically possess an internal skeleton composed of plates of calcium carbonate. In most sea cucumbers, however, these have become reduced to microscopic ossicles embedded beneath the skin. A few genera, such as Sphaerothuria, retain relatively large plates, giving them a scaly armour.[10]

Life history and behaviour[edit] Habitat[edit]

The mysterious Pelagothuria natatrix
Pelagothuria natatrix
is the only truly pelagic echinoderm known to date.

Benthopelagic sea cucumbers, such as this Enypniastes, are often confused with jellyfish, have webbed swimming structures enabling them to swim up off the surface of the seafloor and journey as much as 1,000 m (3,300 ft) up the water column

Spanish dancer (Benthodytes sp.), another swimming sea cucumber, hovering at 2789 meters by the Davidson Seamount

Sea cucumbers can be found in great numbers on the deep seafloor, where they often make up the majority of the animal biomass.[17] At depths deeper than 8.9 km (5.5 mi), sea cucumbers comprise 90% of the total mass of the macrofauna.[18] Sea cucumbers form large herds that move across the bathygraphic features of the ocean, hunting food. The body of some deep water holothurians, such as Enypniastes eximia, Peniagone leander and Paelopatides confundens,[19] is made of a tough gelatinous tissue with unique properties that makes the animals able to control their own buoyancy, making it possible for them to either live on the ocean floor or to actively swim [20] or float over it in order to move to new locations,[21] in a manner similar to how the group Torquaratoridae floats through water. Holothurians appear to be the best adapted echinoderms to extreme depths, and are still very diversified beyond 5,000 m deep: several species from the Elpidiidae
family ("sea pigs") can be found deeper than 9,500 m, and the record seems to be some species of the Myriotrochus genus (in particular Myriotrochus bruuni), identified down to 10,687 meters deep.[22] In more shallow waters, sea cucumbers can form dense populations. The strawberry sea cucumber (Squamocnus brevidentis) of New Zealand
New Zealand
lives on rocky walls around the southern coast of the South Island where populations sometimes reach densities of 1,000 animals per square meter (93 /sq ft). For this reason, one such area in Fiordland
is called the strawberry fields.[23] Locomotion[edit] Some abyssal species in the abyssal order Elasipodida
have evolved to a "benthopelagic" behaviour: their body is nearly the same density as the water around them, so they can make long jumps (up to 1,000 m (3,300 ft) high), before falling slowly back to the ocean floor. Most of them have specific swimming appendages, such as some kind of umbrella (like Enypniastes), or a long lobe on top of the body (Psychropotes). Only one species is known as a true completely pelagic species, that never comes close to the bottom: Pelagothuria natatrix.[24] Diet[edit] Holothuroidea are generally scavengers, feeding on debris in the benthic zone of the ocean. Exceptions include some pelagic cucumbers and the species Rynkatorpa pawsoni, which has a commensal relationship with deep-sea anglerfish.[25] The diet of most cucumbers consists of plankton and decaying organic matter found in the sea. Some sea cucumbers position themselves in currents and catch food that flows by with their open tentacles. They also sift through the bottom sediments using their tentacles. Other species can dig into bottom silt or sand until they are completely buried. They then extrude their feeding tentacles, ready to withdraw at any hint of danger. In the South Pacific sea cucumbers may be found in densities of 40 individuals per square meter (33 /sq yd). These populations can process 19 kilograms of sediment per square meter (34 lb /sq yd) per year.[26] The shape of the tentacles is generally adapted to the diet, and to the size of the particles to be ingested: the filter-feeding species mostly have complex arborescent tentacles, intended to maximize the surface area available for filtering, while the species feeding on the substratum will more often need digitate tentacles to sort out the nutritional material; the detritivore species living on fine sand or mud more often need shorter "peltate" tentacles, shaped like shovels. A single specimen can swallow more than 45 kg of sediment a year, and their excellent digestive capacities allow them to reject a finer, purer and homogeneous sediment. Therefore, sea cucumbers play a major role in the biological processing of the sea bed (bioturbation, purge, homogenization of the substratum etc.).

The mouth of an Euapta godeffroyi, showing pinnate tentacles.

Mouth of a Holothuria
sp., showing peltate tentacles.

Mouth of a Cucumaria miniata, with dendritic tentacles, for filtering the water.

Faeces of an holothurian. This participates in sediment homogenization and purification.

Communication and sociability[edit]

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Sea cucumbers communicate with each other by sending hormone signals through the water. The main aim of communication is reproduction; otherwise they tend to ignore each other. They do not show territorial behaviour. Some species, including abyssal species such as Scotoplanes globosa, can live in groups. Reproduction[edit]

"Auricularia" larva(by Ernst Haeckel).

Most sea cucumbers reproduce by releasing sperm and ova into the ocean water. Depending on conditions, one organism can produce thousands of gametes. Sea cucumbers are typically dioecious, with separate male and female individuals, but some species are protandric. The reproductive system consists of a single gonad, consisting of a cluster of tubules emptying into a single duct that opens on the upper surface of the animal, close to the tentacles.[10] At least 30 species, including the red-chested sea cucumber (Pseudocnella insolens), fertilize their eggs internally and then pick up the fertilized zygote with one of their feeding tentacles. The egg is then inserted into a pouch on the adult's body, where it develops and eventually hatches from the pouch as a juvenile sea cucumber.[27] A few species are known to brood their young inside the body cavity, giving birth through a small rupture in the body wall close to the anus.[10] Development[edit] In all other species, the egg develops into a free-swimming larva, typically after around three days of development. The first stage of larval development is known as an auricularia, and is only around 1 mm (39 mils) in length. This larva swims by means of a long band of cilia wrapped around its body, and somewhat resembles the bipinnaria larva of starfish. As the larva grows it transforms into the doliolaria, with a barrel-shaped body and three to five separate rings of cilia. The "pentacularia" is the third larval stage of sea cucumber, where the tentacles appear. The tentacles are usually the first adult features to appear, before the regular tube feet.[10] Symbiosis
and commensalism[edit]

Emperor shrimp Periclimenes imperator
Periclimenes imperator
on a Bohadschia ocellata sea cucumber

Numerous small animals can live in symbiosis or commensalism with sea cucumbers, as well as some parasites. Some cleaner shrimps can live on the tegument of holothurians, in particular several species of the genus Periclimenes
(genus which is specialized in echinoderms), in particular Periclimenes
imperator.[28] A variety of fish, most commonly pearl fish, have evolved a commensalistic symbiotic relationship with sea cucumbers in which the pearl fish will live in sea cucumber's cloaca using it for protection from predation, a source of food (the nutrients passing in and out of the anus from the water), and to develop into their adult stage of life. Many polychaete worms (family Polynoidae[29]) and crabs (like Lissocarcinus orbicularis) have also specialized to use the mouth or the cloacal respiratory trees for protection by living inside the sea cucumber.[30] Nevertheless, holothurians species of the genus Actinopyga
have anal teeth that prevent visitors from penetrating their anus.[31] Sea cucumbers can also shelter bivalvia as endocommensals, such as Entovalva sp.[32]

Lissocarcinus orbicularis, a symbiotic crab.

imperator, a symbiotic shrimp.

Polynoid worms on a king sea cucumber.

Predators and defensive systems[edit]

Tonna perdix, a selective predator of tropical sea cucumbers.

A sea cucumber in Mahé, Seychelles
Mahé, Seychelles
ejects sticky filaments from the anus in self-defense

Sea cucumbers are often scorned by most of the marine predators because of the toxins they contain (in particular holothurin) and because of their often spectacular defensive systems. However, they remain a prey for some highly specialized predators which are not affected by their toxins, such as the big mollusks Tonna galea
Tonna galea
and Tonna perdix, which paralyzes them using powerful poison before swallowing them completely.[33] Some other less specialized and opportunist predators can also prey on sea cucumbers sometimes when they can't find any better food, such as certain species of fish (triggerfish, pufferfish) and crustaceans (crabs, lobsters, hermit crabs). Some species of coral-reef sea cucumbers within the order Aspidochirotida
can defend themselves by expelling their sticky cuvierian tubules (enlargements of the respiratory tree that float freely in the coelom) to entangle potential predators. When startled, these cucumbers may expel some of them through a tear in the wall of the cloaca in an autotomic process known as evisceration. Replacement tubules grow back in one and a half to five weeks, depending on the species.[5][34] The release of these tubules can also be accompanied by the discharge of a toxic chemical known as holothurin, which has similar properties to soap. This chemical can kill animals in the vicinity and is one more method by which these sedentary animals can defend themselves.[9] Estivation[edit] If the water temperature becomes too high, some species of sea cucumber from temperate seas can aestivate. While they are in this state of dormancy they stop feeding, their gut atrophies, their metabolism slows down and they lose weight. The body returns to its normal state when conditions improve.[5] Phylogeny and classification[edit] See also: List of prehistoric sea cucumbers and List of echinodermata orders

like this Euapta godeffroyi
Euapta godeffroyi
are snake-shaped, without podia, and have pinnate tentacles.

like this Holothuria
cinerascens are sausage-shaped, with peltate tentacles.

like this Cercodemas anceps are curled-bodied and have arborescent tentacles.

like this "sea pig" Scotoplanes
globosa have a translucent body with specific appendages; they live in the abyss.

like this Stichopus herrmanni still lack a definition.

Holothuroidea (sea cucumbers) are one of five extant classes that make up the phylum Echinodermata. Echinodermata is known as one of the most distinctive and diverse phyla ranging from starfish to urchins to sea cucumbers and many other organisms. The echinoderms are mainly distinguished from other phyla by their body plan and organization. While the organisms in this phylum may not all look the same from the outside, their make-up is another story. There are three main characteristics that all echinoderms share. When mature, echinoderms have a pentamerous radial symmetry. While this can easily be seen in a sea star or brittle star, in the sea cucumber it is less distinct and seen in their five primary tentacles. The pentamerous radial symmetry can also be seen in their five ambulacral canals.[35] The ambulacral canals are used in their water vascular system which is another characteristic that binds this phylum together. The water vascular system that develops from their middle coelom or hydrocoel. Echinoderms use this system for many things including movement by pushing water in and out of their podia or "tube feet". Echinoderms tube feet (including sea cucumbers) can be seen aligned along the side of their axes. While echinoderms are invertebrates, meaning they do not have a spine, they do all have an endoskeleton that is secreted by the mesenchyme. This endoskeleton is composed of plates called ossicles. They are always internal but may only be covered by a thin epidermal layer like in sea urchin's spines. In the sea cucumber the ossicles are only found in the dermis, making them a very supple organism. For most echinoderms, their ossicles are found in units making up a three dimensional structure. However, in sea cucumbers the ossicles are found in a two-dimensional network.[36] All echinoderms also possess a trait called mutable collagenous tissues, or MCT.[37] Such tissues can rapidly change their passive mechanical properties from soft to stiff under the control of the nervous system and coordinated with muscle activity. Every class under the phylum Echinodermata has this MCT but uses it in different ways. The Asteroids, sea stars, can detach limbs for self-defense and then regenerate them. The Crinoidea, sea fans, can go from stiff to limp depending on the current for optimal filter feeding. The Echinoidea, sand dollars, use MCT to grow and replace their rows of teeth when they need new ones. The Holothuroidea, sea cucumbers, use MCT to eviscerate their gut as a self-defense response. MCT can be used in many ways but the cellular level and mechanics function the same throughout. One common trend in the uses of MCT is that it is generally used for self-defense mechanisms and in regeneration.[37] Holothuries having no skeleton unlike the other echinoderms, their classification is more complex and their paleontological phylogeny relies on a fistful of well-preserved specimens. The modern taxonomy is based first of all on the presence or the shape of certain soft parts (podia, lungs, tentacles, peripharingal crown) to determine the main orders, and secondarily on the microscopic examination of ossicles to determine the genus and the species. The contemporary genetic methods largely helped to make the classification of these animals progress. Taxonomic classification according to World Register of Marine Species :

order Apodida
Brandt, 1835

family Chiridotidae
Östergren, 1898 family Myriotrochidae Théel, 1877 family Synaptidae
Burmeister, 1837

order Dendrochirotida
Grube, 1840

family Cucumariidae
Ludwig, 1894 family Cucumellidae Thandar & Arumugam, 2011 family Heterothyonidae Pawson, 1970 family Paracucumidae Pawson & Fell, 1965 family Phyllophoridae Östergren, 1907 family Placothuriidae Pawson & Fell, 1965 family Psolidae
Burmeister, 1837 family Rhopalodinidae Théel, 1886 family Sclerodactylidae
Panning, 1949 family Vaneyellidae Pawson & Fell, 1965 family Ypsilothuriidae Heding, 1942

order Elasipodida
Théel, 1882

family Deimatidae Théel, 1882 family Elpidiidae
Théel, 1882 family Laetmogonidae
Ekman, 1926 family Pelagothuriidae
Ludwig, 1893 family Psychropotidae Théel, 1882

order Holothuriida
Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017

family Holothuriidae
Burmeister, 1837 family Mesothuriidae Smirnov, 2012

order Molpadida
Haeckel, 1896

family Caudinidae
Heding, 1931 family Eupyrgidae Semper, 1867 family Gephyrothuriidae Koehler & Vaney, 1905 family Molpadiidae
Müller, 1850

order Persiculida
Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017

family Gephyrothuriidae Koehler & Vaney, 1905 family Molpadiodemidae Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017 family Pseudostichopodidae Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017

order Synallactida
Miller, Kerr, Paulay, Reich, Wilson, Carvajal & Rouse, 2017

family Stichopodidae
Haeckel, 1896 family Synallactidae Ludwig, 1894

Holothurians as food and medicine[edit] Main article: Sea cucumber
Sea cucumber
as food

Dried sea cucumbers in a Japanese pharmacy

To supply the markets of Southern China, Makassar
trepangers traded with the Indigenous Australians
Indigenous Australians
of Arnhem Land. This is the first recorded example of trade between the inhabitants of the Australian continent and their Asian neighbours.[38] There are many commercially important species of sea cucumber that are harvested and dried for export for use in Chinese cuisine
Chinese cuisine
as hoisam.[39] Some of the more commonly found species in markets include:[39][40]

nobilis Thelenota ananas Actinopyga
echinites Actinopyga
palauensis Holothuria
scabra Holothuria
fuscogilva Actinopyga
mauritiana Stichius japonicus Apostichopus
californicus Acaudina molpadioides Isostichopus fuscus

According to the American Cancer Society, although it has been used in traditional Asian folk medicine for a variety of ailments, "there is little reliable scientific evidence to support claims that sea cucumber is effective in treating cancer, arthritis, and other diseases" but there is research being conducted to determine "whether some compounds made by sea cucumbers may be helpful against cancer."[41] There are pharmaceutical companies being built based on gamat, the traditional medicinal usage of this animal.[citation needed] Extracts are prepared and made into oil, cream, or cosmetics. Some products are intended to be taken internally. A single study conducted on an unreported number of mice found intraperitoneal injection of sea cucumber extract to be somewhat effective in high doses (6996099999999999999♠100 ppm or mg/kg) against internal pain, but ineffective against externally induced pain.[42] Another study suggested that the sea cucumber contains all the fatty acids necessary to play a potentially active role in tissue repair.[43] Sea cucumbers are being researched for use in treating a wide number of ailments; including colon cancer.[44] Surgical probes made of nanocomposite material based off the sea cucumber have been shown to reduce brain scarring.[45] One study found that a lectin from Cucumaria echinata impaired the development of the malaria parasite when produced by transgenic mosquitoes.[46]

"Teripang" in a market in Asia.

Sea cucumber
Sea cucumber
in sauce in China.

Haisom cah jamur, Chinese Indonesian sea cucumber with mushroom.

Deep fried
Deep fried
sea cucumbers.

teripang, Indonesian sea cucumber cracker.

Commercial harvest[edit] In recent years, the sea cucumber industry in Alaska has increased due to increased export of the skins and muscles to China.[47] In China, sea cucumbers are farmed commercially in artificial ponds. These ponds can be as large as 400 hectares (1,000 acres) and satisfy much of the local demand.[47] Wild sea cucumbers are caught by divers and these wild Alaskan sea cucumbers have higher nutritional value and are larger than farmed Chinese sea cucumbers. Larger size and higher nutritional value has allowed the Alaskan fisheries to continue to compete for market share, despite the increase in local, Chinese sea cucumber farming.[47] One of Australia's oldest fisheries is the collection of sea cucumber, harvested by divers from throughout the Coral Sea
Coral Sea
in far North Queensland, Torres Straits
Torres Straits
and Western Australia. In the late 1800s there were as many as 400 divers operating from Cook Town, Queensland. Overfishing of sea cucumbers in the Great Barrier Reef is threatening their population.[48] Their popularity as luxury seafood in the Asian countries poses a serious threat to the order Aspidochirotida.[49] Black market[edit] As of 2013 there was a thriving black market in sea cucumbers driven by demand in China where 1 lb (0.5 kg) at its peak might have sold for the equivalent of US$300[50] and a single sea cucumber for about US$160.[51] However, a crackdown by governments both in and out of China reduced both prices and consumption, particularly among government officials who had been known to eat (and were able to afford purchasing) the most expensive and rare species.[51] In the Caribbean Sea
Caribbean Sea
off the shores of the Yucatán Peninsula
Yucatán Peninsula
near fishing ports such as Dzilam de Bravo, illegal harvesting had devastated the population of sea cucumbers and resulted in conflict as rival gangs struggled to control the harvest.[50] The harvested animals are normally dried for selling.[50] Aquaculture[edit] Main article: Aquaculture
of sea cucumber Overexploitation
of sea cucumber stocks in many parts of the world provided motivation for the development of sea cucumber aquaculture in the early 1980s. The Chinese and Japanese were the first to develop successful hatchery technology on Apostichopus
japonicus, prized for its high meat content and success in commercial hatcheries.[52] Using the techniques pioneered by the Chinese and Japanese, a second species, Holothuria
scabra, was cultured for the first time in India in 1988.[53] In recent years Australia, Indonesia, New Caledonia, Maldives, Solomon Islands and Vietnam have also successfully cultured H. scabra using the same technology, which has since been expanded to other species.[52] In art and literature[edit]

Holothurians plate by Ernst Haeckel
Ernst Haeckel
from his Kunstformen der Natur (1904).

Edgar Allan Poe's only novel, The Narrative of Arthur Gordon Pym of Nantucket (1838), includes in its twentieth chapter a long, detailed description of sea cucumbers, which the narrator calls biche de mer. The first movement of French pianist Erik Satie's Embryons desséchés is titled "D'Holothournie". It is said to emulate the "purring" of the Holothourian. Sea cucumbers have inspired thousands of haiku in Japan, where they are called namako (海鼠), written with characters that can be translated as "sea mice" (an example of gikun). In English translations of these haiku, they are usually called "sea slugs». According to the Oxford English Dictionary, the English term "sea slug" was originally applied to holothurians during the 18th century. The term is now applied to several groups of sea snails, marine gastropod mollusks that have no shell or only a very reduced shell, including the nudibranchs. Almost 1,000 Japanese holothurian haiku translated into English appear in the book Rise, Ye Sea Slugs! by Robin D. Gill.[54] Nobel laureate poet Wisława Szymborska
Wisława Szymborska
wrote a poem which mentions holothurians, titled "Autotomy". In the book John Dies at the End, the character Amy Sullivan was nicknamed "Cucumber" by the narrator/author when the two were children. This is assumed by other characters to have a sexual connotation but is actually a reference to her frequent nausea. The name is in reference to a sea cucumber's use of vomiting as a method of self-defense. A descriptive passage in American novelist and MacArthur Fellow Cormac McCarthy's 1985 anti-Western Blood Meridian
Blood Meridian
likens cactus embers to holothurians: "In the thorn forest through which they'd passed the little desert wolves yapped and on the dry plain before them others answered and the wind fanned the coals that he watched. The bones of cholla that glowed there in their incandescent basketry pulsed like burning holothurians in the phosphorous dark of the sea's deeps." In more recent times, the web comic Jerkcity has incorporated references to sea cucumbers. See also[edit]

has information related to Holothuroidea

Wikimedia Commons has media related to Holothuroidea.

Gamat Trepanging


^ "Catch" collagen has two states, soft and stiff, that are under neurological control.Jose del Castillo and David S. Smith. (1996) "We Still Invoke Friction and Occam's Razor to Explain Catch in the Spines of Eucidaris Tribuloides." Biological Bulletin 190:243-244


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v t e

Principal commercial fishery species groups


Large pelagic fish

Mackerel Salmon Saury Shark Swordfish Tuna

albacore bigeye Atlantic bluefin Pacific bluefin southern bluefin skipjack yellowfin

Forage fish

Anchovy Capelin Herring Ilish Menhaden Sardines Shad Sprat


Demersal fish

Catfish Cod

Atlantic Pacific Alaska pollock


flounder halibut plaice sole turbot

Haddock Mullet Orange roughy Pollock Rockfish Smelt-whitings Toothfish

Freshwater fish

Carp Sturgeon Tilapia Trout

Other wild fish

Eel Whitebait more...


Crab Krill Lobster Shrimp more...


Abalone Mussels Octopus Oysters Scallops Squid more...


Sea cucumbers Sea urchin more...



bighead common crucian grass silver

Catfish Freshwater prawns Gilt-head bream Mussels Oysters Salmon

Atlantic salmon trout coho chinook

Scallops Seaweed Shrimp Tilapia

Commercial fishing World fish production Commercial species Fishing topics Fisheries glossary

Authority control

NDL: 00568004

Taxon identifiers

Wd: Q127470 ADW: Holothuroidea EoL: 2012 Fossilworks: 31227 GBIF: 222 ITIS: 158140 NCBI: 7705 W